Parabolic trough-type solar dish collector

Written by Scott Sowers

Hold a magnifying glass in a sunbeam and focus the light until it generates heat. This simple experiment is the basic premise behind concentrated solar power or “CSP.” Take the example of the magnifying glass and imagine acres of parabolic mirrors in the desert and you have enough megawatts to power a city – without burning any fossil fuels.

The concept isn’t that new but it’s being pushed to the forefront by the combination of rising fuel prices and government incentives in Spain, Portugal, France, Greece and Israel. Advances in technology are also getting the movement off the ground but the natural progression of science and economics may be providing the biggest push.

“It’s an evolution of many small steps,” says Avi Brenmiller, CEO of Solel, an Israeli-based, leading manufacturer in CSP. “As we move from small projects to big projects it’s easier for the bankers to understand,” he says. Brenmiller is an engineer who took the helm at Solel after gaining experience in core collector technology by working for Luz, a solar company that went under in 1991. Belgian investors saw promise in the firm’s assets, pumped in cash and gave rise to Solel. Brenmiller has never looked back and sees a future shining with opportunity. “In five years time there will be thousands of megawatts of CSP installed world wide,” he says.

The short term is also looking up. According to Brenmiller, Solel is currently working on plants and deals in Spain that will contribute to 6000 megawatts of solar generated power. The country is seen as the current leader in concentrated solar use. “Spain is the model for how to do things right,” says Brenmiller, “private industry, the banks and the government are all onboard with it.”

The other big news coming out of Solel is a US-based project. Last July the firm inked a deal with Pacific Gas and Electric which will purchase solar power from a Solel 500 megawatt project in the Mojave desert. It will be the largest solar project in the world, covering 6,000 acres. The plant will use 1.2 million mirrors, produce enough power for 550,000 homes, and cost an estimated $2 billion.

The hardware of the operation consists of evacuated tubes that function like empty thermos bottles lying in the sun and collecting heat. The heat is focused by mirrors that are computer controlled to track the sun’s arc through the sky. Temperatures inside the tubes can reach seven hundred fifty degrees. The heat is transferred to a liquid that’s used to heat water until it becomes steam. The steam spins turbines that generate electricity.

The system holds great promise and has been used to generate power in Southern California since the 1980’s but it’s still a ways from being cheap or easy. “Cost and efficiency are critical in building the plants,” says Kevin Swartz, Solel’s president of US operations, “plus like any power plant you have to find that right site. You need large sections of land where it’s sunny.”

Swartz comes onboard after spending twenty five years working in the natural gas industry. That experience will come in handy if the industry goes the way Brenmiller sees it heading. “We can now see how a hybrid plant could be the answer for those days when the sun doesn’t shine,” he says. “It would be set up as eighty percent solar, twenty percent gas.” Unlike a traditional coal or gas fired plant, solar power only generates electricity when the sun is out– which is the time of peak power demands. A clean burning, natural gas back-up system would hedge everybody’s bets.

Building new power plants in the areas where the sun shines the most usually requires running new transmission lines, which is always a sticky area for permitting. But market forces are already driving the renewable train. “Look at the increased value of energy,” says Brenmiller, “you can’t grow national economies without energy.” He, along with every other energy expert, points to the surging economies in China and India and the effect they will have on energy supplies that aren’t growing as fast as worldwide demand.

Solar, thermal-based power or using the sun to heat water has never come across as sexy as it’s solar sister, photo voltaic produced power. PV uses a chemical reaction in roof mounted panels to produce direct current and is also seeing surging growth around the world. According to industry sources, companies like BP Solar are having trouble keeping up with an ever increasing demand for solar panels.
The drive towards all things solar is also spilling over into smaller solar thermal companies who are marketing to homeowners instead of governmental bodies. Apricus is a Connecticut-based firm with a parent company in Australia and manufacturing facilities in China. Their evacuated tubes are scaled down for residential use and provide heat for domestic hot water or can be used to heat a house using radiant systems. Apricus is also doing booming business. “We were up four to five hundred percent last year and we expect to be up six hundred percent this year,” says Stephen Elkin, CEO. “But the biggest users are in Germany,” he says.

Even not-so-sunny Eastern Europe is making use of solar thermal as the systems become more efficient and affordable. Private industry has also become interested in systems marketed by Solel that are designed as free standing, off the grid power systems. The co-generation systems provide heat, power and air conditioning. Solel’s current workload in building solar power plants is taking center stage as Brenmiller reflects on a vocation that’s also turned into a spiritual journey. I’m a mechanical engineer,” he says, “but I’ve always wanted to do something that’s good for the soul.”

Events like the Washington International Renewable Energy Conference provide a forum for the sharing of ideas that are changing the way energy will be thought about and consumed in the future. “WIREC is good for getting more exposure to the issues,” says Brenmiller,” there’s still a lot of people out there who don’t know that there are solutions to the energy problem that we can implement right now.”